J 2016

Research of the Chemical Heterogeneity during Crystallization for AlCu4MgMn Alloy and the Possibility of its Elimination

WEISS, Viktorie

Základní údaje

Originální název

Research of the Chemical Heterogeneity during Crystallization for AlCu4MgMn Alloy and the Possibility of its Elimination

Název česky

Výzkum chemické heterogenity během krystalizace AlCu4MgMn slitiny a možnosti jejího odstranění

Autoři

WEISS, Viktorie (203 Česká republika, garant, domácí)

Vydání

Manufacturing Technology, Ústí nad Labem, J. E. Purkyne University, 2016, 1213-2489

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

20501 Materials engineering

Stát vydavatele

Česká republika

Utajení

není předmětem státního či obchodního tajemství

Kód RIV

RIV/75081431:_____/16:00000630

Organizační jednotka

Vysoká škola technická a ekonomická v Českých Budějovicích

Klíčová slova česky

homogenizační žíhání; AlCu4MgMn slitina; krystalová segregace; EDX analýza; obrazová analýza

Klíčová slova anglicky

homogenization annealing; AlCu4MgMn alloy; crystal segregation; EDX analysis; image analysis

Štítky

Změněno: 19. 7. 2016 13:38, Věra Kostková

Anotace

V originále

Crystal segregation is taken as chemical heterogeneity under the micro-scale and it develops during the crystalli-zation process. Alloy crystallization does not take place under a particular temperature, as it happens in the case of pure metals, but it runs under a certain temperature interval. When cooling the melt, various places start devel-opment among dendritic cells which differ in their chemical composition. Crystal segregation can be generally defined as chemical heterogeneity developing during the alloy crystallization process, and it can be either en-riched or in contrast depleted with alloying elements and impurities, which are unevenly segregating over the en-tire dendritic surface. In the central part of the dendritic cells there is an alloy, which is depleted with alloying elements, while the edge areas of dendritic cells and interdendrite space present higher concentration of alloying elements. This concentration shows a hyperbolic development; when the central part of dendritic cells area has the lowest alloying elements concentration, while the edge part of a dendritic tree and the interdendrite space show the maximum concentration. The distance between two main axes of dendritic cells is affected by the temperature interval running between the liquid and solid phase of the chosen alloy, as well as by melt cooling rate and temper-ature gradient during the solidification phase. The shorter distance between the axes of dendritic cells appears under faster cooling, which allows very fast heat dissipation and creates very fine structure of the resulting alloy. The longer distance between the main axes of dendritic cells stimulates greater segregation appearing under slow melt cooling. Crystal segregation formation of aluminum alloys enriched with alloying elements and impurities cannot be pre-vented, only its extension can be regulated and it can be suppressed with the correct choice of heat treatment pa-rameters. To suppress the crystal segregation the casts should undergo heat treatment which is called homogenization annealing.